From e5ef0cad9a78d6db3aa94c4f83486b9ee7ab5f8c Mon Sep 17 00:00:00 2001
From: Tamo <tamo@meilisearch.com>
Date: Tue, 7 Sep 2021 12:11:03 +0200
Subject: [PATCH] use meters in the filters

---
 milli/Cargo.toml                           |  1 +
 milli/src/lib.rs                           |  8 ++++++++
 milli/src/search/facet/filter_condition.rs | 13 ++++++++-----
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/milli/Cargo.toml b/milli/Cargo.toml
index d2767afd4..be507332e 100644
--- a/milli/Cargo.toml
+++ b/milli/Cargo.toml
@@ -16,6 +16,7 @@ flate2 = "1.0.20"
 fst = "0.4.5"
 fxhash = "0.2.1"
 grenad = { version = "0.3.1", default-features = false, features = ["tempfile"] }
+haversine = "0.2.1"
 heed = { git = "https://github.com/Kerollmops/heed", tag = "v0.12.1", default-features = false, features = ["lmdb", "sync-read-txn"] }
 human_format = "1.0.3"
 levenshtein_automata = { version = "0.2.0", features = ["fst_automaton"] }
diff --git a/milli/src/lib.rs b/milli/src/lib.rs
index a3cede1fd..3c7713308 100644
--- a/milli/src/lib.rs
+++ b/milli/src/lib.rs
@@ -142,6 +142,14 @@ where
     Some((head, tail))
 }
 
+/// Return the distance between two points in meters
+fn distance_between_two_points(a: &[f64; 2], b: &[f64; 2]) -> f64 {
+    let a = haversine::Location { latitude: a[0], longitude: a[1] };
+    let b = haversine::Location { latitude: b[0], longitude: b[1] };
+
+    haversine::distance(a, b, haversine::Units::Kilometers) * 1000.
+}
+
 #[cfg(test)]
 mod tests {
     use serde_json::json;
diff --git a/milli/src/search/facet/filter_condition.rs b/milli/src/search/facet/filter_condition.rs
index a36fddb01..08a84899f 100644
--- a/milli/src/search/facet/filter_condition.rs
+++ b/milli/src/search/facet/filter_condition.rs
@@ -504,17 +504,20 @@ impl FilterCondition {
             LowerThan(val) => (Included(f64::MIN), Excluded(*val)),
             LowerThanOrEqual(val) => (Included(f64::MIN), Included(*val)),
             Between(left, right) => (Included(*left), Included(*right)),
-            GeoLowerThan(point, distance) => {
+            GeoLowerThan(base_point, distance) => {
                 let mut result = RoaringBitmap::new();
                 let rtree = match index.geo_rtree(rtxn)? {
                     Some(rtree) => rtree,
                     None => return Ok(result),
                 };
 
-                let iter = rtree
-                    .nearest_neighbor_iter_with_distance_2(point)
-                    .take_while(|(_, dist)| dist <= distance);
-                iter.for_each(|(point, _)| drop(result.insert(point.data)));
+                rtree
+                    .nearest_neighbor_iter(base_point)
+                    .take_while(|point| {
+                        dbg!(crate::distance_between_two_points(base_point, point.geom()))
+                            < *distance
+                    })
+                    .for_each(|point| drop(result.insert(point.data)));
 
                 return Ok(result);
             }